Multi-infarct dementia (MID), the second major cause of dementia among the elderly, is a growing health problem. Although much has been learned about the pathophysiology of this disease, little is known about the etiological factors. We propose to seek information about epidemiologic, medical, stroke-specific and other clinical factors by carrying out a case-control study among stroke patients who do or do not develop MID. We will utilize epidemiologic interview together with psychologic testing, medical records, physical examination, psychiatric interview, and cranial computed tomography in 60 index cases and 120 control subjects to gather data about risk factors for dementia in stroke patients. Longitudinal study will be carried out to determine morbidity, mortality and outcome of cognitive impairment.